lunes, 15 de junio de 2015

"A Turkish Delight". Carla Lagendijk

Me es grato publicar hoy, un artículo de Carla Lagendijk, de nacionalidad holandesa, con quien comparto la afición del coleccionismo de arenas y sobre todo, su amistad.
Agradezco a la autora su colaboración en mi blog.




During one of my vacations in Turkey,  I got the opportunity to visit the beautiful lake Salda [in turkish: Salda Gölü] , one of the deepest lakes in Turkey. It is lying in the southwest Anatolia region, in the province of Burdur , 4 km. WNW of Yesilova.
Driving along the E 87 into the direction of the ancient site of Hierapolis and the impressive travertine  terraces of Pamukkale,  there comes an exit to the right at a petrol station. It is road D 330, which leads to the lake and Yesilova [about 40 km]: a lake I was very eager to see, especially for its white mineral along its coast!

The lake is originally a crater lake and is lying at a mean height of 1139 metres above sea level.  The bowl shaped lake is about 8 km. in length from north to south and 6 km from east to west and its deepest point is 184 m.
There are only 2 rivers flowing into the lake but there is no discharge.
It is thought to be the cleanest and certainly the clearest lake of Turkey!
Except for its vegetation it looks like being on a Caribbean island with the blue water and the white material on the beaches.  

The speciality of this lake is that the water contains sodium carbonate and due to geothermal activities in the surface water this water never freezes during winter time, although the warm water temperature causes a thick fog hovering over the lake during the cold winter months.
But this time of year [ May] it was quite warm. Several Turkish families were enjoying their weekend picnic under the trees along the lake, where it was deliciously cool.
Arrived on the shore I saw what I was actually looking for: it was a stunning sight: a thick white material everywhere on the beach close to the water. Sometimes in lumps with a silky appearance, but also in fine grains. The top of the beaches consist out of the original grey-brown material from the area, from large blocks to grains.

The white mineral is hydro magnesite, a hydrated magnesium carbonate mineral and is the main characteristic of the lake. It accumulates  on the beaches along the water line in the south and south-west of the lake, more or less mixed with the dark grey stones and grains.

The geology of the area can be described as follows:
The mountains in this region mainly consist out of an Upper Cretaceous  ophiolitic rock mass. It is an, by tectonic movements, upheaved old ocean floor but the ophiolite has been altered by the geo thermal activities and the chemical composition of the surface water into for instance serpentinite and harzburgite.
Tertiary  limestone [ dolomite] occurs in the east of the lake .
On the bottom and along the lake are the Quaternary  sediments.

The source of the hydro magnesite is the magnesite deposit in veins of the altered ophiolite. That the hydro magnesite has been formed and is still being formed on the bottom of the lake under natural circumstances  is rather special! It seems that the hydraulic and the climatologic conditions in and around the lake are ideal to form the mineral. The water has a constant warm temperature.
The dark grey-brown sediment is altered ophiolite of which  large quantities  are also being transported to the lake by the 2 rivers.

Needless to say that this lake shore with its white "sand" and surrounded by grass and trees is an ideal place for adults and children to relax and ……for sand collectors to look around on the beaches and collect their samples. An advantage is that hydromagnesite is very light in weight too!

So, if you ever come into the neighbourhood, maybe on your way to Pamukkale,  turn off the main road if you have the possibility and the time and proceed into the direction of Yesilova.
It is worth the detour, even if you are not a collector of sand samples!


Carla Lagendijk.

Sand samples collector.
                                   
   Lake Salda 
    Lake Salda.  Hydromagnesite

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